The invention relates to a horizontal scan linearizing circuit for use with cathode ray tube (CRT) yokes such as those employed in video camera viewfinders.
To provide horizontal scanning in a CRT via a control the yoke, a ramp current is applied to yoke during the active scan line interval of the video signal. However, the ramp current in the yoke is non-linear due to the resistive losses in the yoke and in the associated drive circuitry. It is desirable that this non-linearity be corrected.
Prior art linearizing schemes typically employ linearizing inductors with adjustable magnets, in series with the inductor which forms the yoke, or employ a technique using linear current driving yokes, to correct the scan non-linearity. However, the linear current driving yoke technique is somewhat inefficient for viewfinder applications. On the other hand, the inductors of the inductor technique are relatively large and bulky. Since it is a well known fact that size and weight are critical parameters in the design of color cameras, particularly in portable camera systems wherein power is supplied by a battery pack, the inductor technique is somewhat impractical for use in lightweight, i.e., portable, camera apparatus.